Method and tools for implanted device

ABSTRACT

A method and toolset capable of remotely moving a rotor of an implanted device in a first arcuate direction and detecting a first limit of travel, moving the rotor in a second, opposite direction and detecting a second limit of travel without altering the current performance setting of the implanted device, comparing the first and second limits of travel with known values for a plurality of selectable performance settings, and indicating the current performance setting of the implanted device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.14/725,240, filed on May 29, 2015 which is a divisional of U.S.application Ser. No. 13/929,998, filed on Jun. 28, 2013, which is acontinuation-in-part of U.S. application Ser. No. 13/705,009, filed onDec. 4, 2012, which is a divisional of U.S. application Ser. No.12/858,193 filed Aug. 17, 2010, now U.S. Pat. No. 8,322,365, both ofwhich are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to techniques and tools to determine location,orientation and adjustment of implanted medical devices and moreparticularly to location, orientation and adjustment of adjustable valvemechanisms which resist unintentional performance setting changes.

2. Description of the Related Art

There are a number of treatments for medical conditions which requirefluid to be removed from an organ or tissue of a patient. One suchcondition is hydrocephalus, where cerebrospinal fluid abnormallyaccumulates in the skull faster than it is withdrawn by the body. Theexcessive build-up of cerebrospinal fluid compresses brain tissues,which eventually leads to brain damage.

Hydrocephalus is commonly treated by implanting a shunt in fluidcommunication with a ventricle within the brain to withdrawcerebrospinal fluid at a desired rate. Typically, the rate of withdrawalof cerebrospinal fluid is controlled by a valve having differentpressure settings which a clinician adjusts pre-operatively. A number ofshunt valves can be noninvasively changed after implantation, such asthe Codman® Hakim® programmable valve which is currently commerciallyavailable from Codman & Shurtleff, Inc. of Raynham, Mass. Otheradjustable valves include the Strata™ valve from Medtronic Neurosurgery,the ProGAV™ valve manufactured by Christoph Meithke GMBH and distributedby Aesculap AG, and the Sophy™ and Polaris™ valves available fromSophysa USA Inc. All of these valves utilize applied magnet fields, suchas those generated by magnets, to adjust valve pressure settings. Todiffering degrees, these valves are not optimal regarding resistance tounintentional setting changes, ease of use in achieving the desiredvalve setting, and detection of actual valve setting.

Detection of one or more parameters of an implanted device is disclosedgenerally by Hakim et al. in U.S. Pat. No. 4,608,992. Non-invasiveadjustment of implanted valves is described generally by Hooven in U.S.Pat. No. 4,676,772. Some techniques for determining the location andorientation of an indwelling medical device are disclosed by Haynor etal. in U.S. Pat. Nos. 5,879,297 and 6,216,028. More recent techniquesand tools include those disclosed by Bertrand et al. in U.S. PatentPublication Nos. 2002/0022793 and 2005/0092335, and by Girardin et al.in U.S. Patent Publication No. 2011/0105993, for example.

Magnetic resonance imaging, also referred to as MRI, is an increasinglycommon procedure for examining one or more regions of a patient. MRIprovides better contrast between tissue types than computed tomographyand utilizes powerful magnetic fields instead of potentially harmfulx-rays. While magnetic exposure levels from first generation MRI systemswere typically up to 1.5 Tesla, newer MRI machines routinely use 3.0Tesla. As recognized by McCusker et al. in U.S. Pat. No. 7,390,310, forexample, such strong magnetic fields can interfere with implanteddevices including shunt valves.

As of the filing date for the present application, the Codman® CERTAS™programmable valve is currently commercially available from Codman &Shurtleff, Inc. of Raynham, Mass. The CERTAS™ valve was disclosed andclaimed in the parent application, now U.S. Pat. No. 8,322,365, and isgenerally resistant to MRI exposure up to at least 3.0 Tesla withoutunintentionally changing the valve setting. Intentional valve adjustmentis accomplished using a suitably aligned magnetic field. Correctpositioning of the applied magnetic field relies on the user.

It is therefore desirable to have simplified and more accuratetechniques and tools to locate, determine orientation, and adjustimplantable valves capable of withstanding strong magnetic fields andwhich resist unintended changes to valve settings.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved method andtools to locate, determine orientation, and adjust as desired animplanted valve unit which resists unintentional performance settingchanges when the unit is subjected to vibration, jarring or unintendedmagnetic fields.

Another object of the present invention is to provide such positioningmethods and tools which readily and accurately allow desirednon-invasive changes to pressure or flow control settings of theimplanted valve unit.

It is yet another object of this invention to enhance detection of theactual valve opening pressure setting or flow control setting.

This invention features a method of positioning a toolset on theexterior of a patient relative to a magnetically adjustable deviceimplanted in the patient, the implanted device including a rotor havingan axis of rotation and at least one rotor magnet, the rotor having arange of arcuate motion within each of a plurality of selectableperformance settings without altering a selected performance setting forthe implanted device. The method includes estimating a location on theexterior of the patient above the implanted device, moving the toolsetto the estimated location, detecting the location of at least one of amaximum positive pole value and a maximum negative pole value of therotor magnet at a current performance setting, and moving the toolsetrelative to the at least one detected maximum pole value. Preferably,the method further includes moving the rotor in a first arcuatedirection and detecting a first limit of travel without altering thecurrent performance setting, moving the rotor in a second, oppositedirection and detecting a second limit of travel without altering thecurrent performance setting, comparing the first and second limits oftravel with known values for the plurality of selectable performancesettings, and indicating the current performance setting of theimplanted device.

In some embodiments, the implanted device is a valve unit havingadjustable performance settings to regulate passage of a bodily fluid.The valve unit includes a casing defining a port, such as an inlet or anoutlet for the bodily fluid, and a valve mechanism positioned at theport. The valve mechanism includes a movable valve member. The valveunit further includes a rotor disposed at a first location in the casingand having an axle which turns about an axis of rotation. The rotordefines a plurality of radially flat cam surfaces, each cam surfaceoccupying an arc about the axis of rotation. A spring arm unit, disposedat a second location in the casing, has a cam follower arm in slidablecontact with the cam surfaces of the rotor and has a resilient springelement applying a closing effect with the valve member at the port toestablish a performance setting for the valve unit. Sufficient rotationof the rotor to change the cam surface in contact with the cam followeralters the closing effect with which the valve member moves relative tothe port and thereby alters the performance setting of the valve unit.

This invention also features a positioning toolset suitable forindicating and adjusting the current performance setting of amagnetically adjustable device implanted in a patient, the implanteddevice having at least one magnet aligned with the current performancesetting of the device. The toolset includes an indicator tool with atleast one sensor that detects the location of the implanted device anddetermines the current performance setting of the implanted device. Theindicator tool is capable of guiding a user to move the indicator toolto an optimum position relative to the implanted device and including atleast one locating feature to designate the optimum position of theindicator tool. The toolset further includes an adjustment tool havingat least one adjustor magnet and at least one locating feature to alignthe adjustment tool with the optimum position of the indicator tool, theadjustor magnet being movable relative to the at least one locatingfeature to change the performance setting of the implanted device.

In some embodiments, the at least one locating feature of the indicatortool is independent from the at least one locating feature of theadjustment tool. In one embodiment, at least one of the locatingfeatures of the indicator tool and the adjustment tool is a markingguide capable of assisting a user in placing and aligning a referencemark on a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

In what follows, preferred embodiments of the invention are explained inmore detail with reference to the drawings, in which:

FIG. 1 is a schematic perspective exploded view of a novel programmableshunt valve device having an improved adjustable valve unit;

FIG. 1A is a side cross-sectional view of an alternative programmableshunt valve device having another novel adjustable valve unit;

FIG. 2 is an exploded perspective view of the adjustable valve unit ofFIG. 1;

FIG. 3 is a top view of the adjustable valve unit of FIG. 2;

FIG. 4 is a side cross-sectional view of the adjustable valve unit ofFIG. 3 along lines 4-4;

FIG. 5 is a cross-sectional view of the adjustable valve unit of FIG. 3along lines 5-5;

FIG. 6 is a partial cross-sectional view of the adjustable valve unit ofFIG. 4 approximately along lines 6-6 at a first pressure setting;

FIG. 6A is a deeper cross-sectional view of the adjustable valve unit ofFIG. 4 approximately along lines 6A-6A at a first pressure setting;

FIGS. 6B-6H are partial cross-sectional views of the adjustable valveunit of FIG. 4 at different, successive pressure settings;

FIG. 7 is a deeper cross-sectional view of the adjustable valve unit ofFIG. 4 approximately along lines 7-7;

FIG. 8 is a cross-sectional view of the adjustable valve unit of FIG. 7showing the transition to a different pressure setting;

FIG. 9 is a perspective view of the spring arm unit with optionaltorsion spring;

FIG. 9A is a top plan view of the element of FIG. 9;

FIG. 10 is a side cross-sectional view of the adjustable valve unit ofFIG. 8 along lines 10-10 showing axial lifting of the rotatableconstruct;

FIG. 11 is a shallower partial top cross-sectional view of theadjustable valve unit of FIG. 6H showing the “virtual off” position inan unconstrained condition;

FIG. 12 is a side view along lines 12-12 of FIG. 11;

FIG. 13 is a side cross-sectional view along lines 13-13 of FIG. 11;

FIG. 13A is a partial cross-sectional view along lines 13A-13A of FIG.13;

FIG. 14 is a perspective view of a tool set according to the presentinvention including an indicator tool, a locator tool, and a settingadjuster tool;

FIG. 15 is an exploded perspective view of the indicator tool of FIG.14;

FIG. 16 is a top plan view of the locator tool of FIG. 14 positionedover an implanted valve;

FIG. 17 is a side cross-sectional view along lines 17-17 of FIG. 16,showing in phantom the shunt valve implanted under the skin in apatient;

FIG. 18 is a top plan view of the indicator tool nested with the locatortool;

FIG. 18A is a side cross-sectional view along lines 18A-18A of FIG. 18;

FIG. 19 is a side cross-sectional view along lines 19-19 of FIG. 18 witha release button in a normal, engaged position;

FIG. 19A is a partial side cross-sectional view along lines 19-19 ofFIG. 18 showing the release button in a depressed, disengaged position;

FIG. 20 is a partial cross-sectional view along lines 20-20 of FIG. 18;

FIG. 21 is an exploded view of the setting adjuster tool of FIG. 14;

FIG. 22 is a top plan view of the adjuster tool nested with the locatortool;

FIG. 22A is a partial cross-sectional view along lines 22A-22A of FIG.22;

FIG. 23 is a partial cross-sectional view along lines 23-23 of FIG. 22;

FIG. 24 is an exploded view of an alternative indicator tool accordingto the present invention;

FIG. 25 is a side cross-sectional view along lines 25-25 of FIG. 24;

FIG. 26 is a cross-sectional view of another alternative indicator toolaccording to the present invention positioned in a locator tool;

FIG. 27A is a top plan view of an adjuster tool positioned over apatient with the locator tool omitted;

FIG. 27B is a schematic cross-sectional view along lines 27B-27B of FIG.27A showing only the adjuster tool and a portion of the shunt valve withvalve unit, shown at 10X scale;

FIG. 28 is a schematic side view of the distal portion of an alternativemovable valve member with a port restricting element to control flow ofbodily fluid;

FIG. 29 is a partial top cross-sectional view along lines 29-29 of FIG.28;

FIG. 30 is a schematic side view of yet another movable valve member;

FIGS. 31 and 31A are schematic top and side views of a positioning toolof a positioning toolset according to the present invention;

FIGS. 32 and 32A are schematic top and side views of an alternativepositioning tool according to the present invention;

FIGS. 33 and 33A are schematic top and side views of an adjustment toolfor use with the positioning tools of FIGS. 31 and 32;

FIGS. 34 and 34A are schematic top and side views of an alternativeadjustment tool for use with the positioning tool of FIGS. 32;

FIGS. 35 and 36 are flow charts showing one technique according to thepresent invention to optimize tool location;

FIG. 37 is a flow chart illustrating optimization of tool position suchas by changing roll or pitch of the tool;

FIG. 38 is a flow chart showing optimization of tool orientation;

FIG. 39 is a flow chart showing optional further steps to optimize toolorientation;

FIG. 40 is a schematic diagram of three sensor arrays for a positioningtool according to the present invention, each array sensing X, Y and Zaxes;

FIGS. 41A and 41B are examples of displayed mode and guidance to a user,respectively, for the display screens shown in FIGS. 31 and 32;

FIGS. 42A-42C are top views of alternative displays guiding a user;

FIG. 43 is a schematic perspective view of an alternative detection toolof an additional positioning toolset according to the present invention;

FIG. 44 is a schematic perspective view of an alternative locator toolaccording to the present invention;

FIG. 45 is a schematic perspective view of an alternative adjustmenttool according to the present invention;

FIG. 46 is a schematic perspective view of yet another detection toolaccording to the present invention with marking guides; and

FIG. 47 is a schematic perspective view of yet another adjustment toolaccording to the present invention with marking guides similar to thoseof FIG. 46.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Several constructions of a positioning toolset, also referred to as apositioning system, according to the present invention have apositioning tool and an adjustment tool such as shown and describedbelow in relation to FIGS. 14-47. This invention may be accomplished bypositioning a toolset on the exterior of a patient relative to amagnetically adjustable device, such as a valve unit implanted in thepatient. The implanted valve unit or other device includes a rotorhaving an axis of rotation and at least one rotor magnet, the rotorhaving a range of arcuate motion within each of a plurality ofselectable performance settings without altering a selected performancesetting for the implanted device. The method includes estimating alocation on the exterior of the patient above the implanted device,moving the toolset to the estimated location, detecting the location ofat least one of a maximum positive pole value and a maximum negativepole value of the rotor magnet at a current performance setting, andmoving the toolset relative to the at least one detected maximum polevalue. Preferably, the method further includes moving the rotor in afirst arcuate direction and detecting a first limit of travel withoutaltering the current performance setting, moving the rotor in a second,opposite direction and detecting a second limit of travel withoutaltering the current performance setting, comparing the first and secondlimits of travel with known values for the plurality of selectableperformance settings, and indicating the current performance setting ofthe implanted device. Certain details on the method are provided belowin relation to FIGS. 35-39.

A preferred application for an adjustable valve unit suitable for useaccording to the present invention is within a single use implantablevalve device as part of a system for shunting cerebrospinal fluid totreat hydrocephalus. It is desirable for the valve unit to have a numberof different pressure settings for constant, controlled intraventricularpressure and drainage of cerebrospinal fluid. Preferred opening pressuresettings preferably range from approximately 30 mm to 210 mm water (294Pa to 2,059 Pa) in seven increments of 30 mm (294 Pa), with a finalsetting of approximately at least 400 mm water (3,920 Pa) to minimizeflow as a “virtual off” setting, that is, as substantially closed. Aclinician can select and set the initial opening pressure of the valvepre-operatively. After implantation, the pressure setting can be changednoninvasively using a toolset according to the present invention.

FIG. 1 illustrates a programmable shunt valve device 10 having a shunthousing 12, preferably formed of a translucent material such assilicone, with proximal connector 14 and distal connector 16. Aventricular catheter or other proximal catheter is connectable toconnector 14 to bring fluid into shunt housing 12. Fluid passes intosampling or pumping chamber 18 and then through a valve mechanism ininlet 102 into novel adjustable valve unit 100, which is shown anddescribed in more detail below in relation to FIGS. 2-13A. Valve unit100, FIG. 1, includes a casing 103 formed as upper casing 104 and lowercasing 106 which are joined by sonic welding in this construction. Aneedle guard 20, preferably formed of a rigid polymeric material, andlower casing 106 are secured within housing 12 by a backing plate 22,preferably formed of silicone reinforced with a polymeric mesh, which isbonded to housing 12 by a medical grade epoxy.

When fluid pressure at inlet 102 exceeds a selected pressure settingwithin valve unit 100, fluid is admitted past a valve mechanism and thenflows through valve unit outlet 110 into passage 30 of housing 12.Preferably, a Siphonguard® device, which is currently commerciallyavailable from Codman & Shurtleff, Inc. of Raynham, Mass., is disposedwithin passage 30. The Siphonguard® device (not shown) is designed toprevent excessive drainage of cerebrospinal fluid by a shunt system. Onecause of excessive draining is a change in patient position from asupine to an upright position. Ultimately, fluid exits from housing 12through distal connector 16 into a peritoneal catheter or other distalcatheter.

An alternative shunt valve device 10 a is shown in cross-section in FIG.1A having a shunt housing 12 a, proximal connector 14 a with epoxy seals13 and 15, and distal connector 16 a with epoxy seals 17 and 19. Needleguard 20 a and backing plate 22 a form the floor of chamber 18 a. Fluidflows into novel valve unit 100 a through inlet 102 a defined by lowercasing 106 a and exits through outlet 110 a, defined by upper casing 104a in this construction, into a small chamber 40 and then directly intodistal connector 16 a. More details on the components within valve units110 and 110 a are provided below.

Valve unit 100, FIG. 2, includes rotor 120, spring arm unit 130, valvemechanism 140, and a rotor retention spring 150. In this constructionrotor 120, also referred to as a rotating construct, is formed of alower cam structure 122 having a plurality of radially flat camsurfaces, as shown and described in more detail below, and an upper,magnet housing 124 carrying magnetic elements 123 and 125. Housing 124also defines a finger 127 which engages a stop in upper casing 104 whenrotor 120 is moved to an unconstrained condition as described below.Rotor 120 rotates about axle 126 which defines a substantially fixedaxis of rotation R at a first location in casing 103.

Preferably, rotor 120 is also capable of moving along the axis ofrotation, in a translational motion, to an unconstrained condition whenan adjuster tool is applied to it as described in more detail below.Retention spring 150 biases rotor 120 to a downward, normallyconstrained condition. Preferably, spring 150 is a coil spring havingsufficient bias to resist the effect of gravity, regardless of theposition of the valve unit, and to resist magnetic or ferrous objects,such as magnets in an indicator tool described in more detail below.However, spring 150 is insufficient to resist the effects of anadjustment tool, also described below. Lower cam section 122 has asufficient height to ensure that cam follower 132 remains in contactwith a cam surface in both the constrained and unconstrained conditions.

Spring arm unit 130 includes cam follower 132, a resilient springelement 134, and upper and lower axles 136 and 138 at a second locationin casing 103. Axle 138 turns about a bearing 139 formed of alow-friction, hard material such as synthetic ruby. It is desirable forcasing 103, rotor 120 and spring arm unit 130 to be formed ofpolyethersulfone, while all spring components are formed of medicalgrade non-ferromagnetic stainless steel.

Valve mechanism 140 includes seat 142 and movable valve member 144.Preferably, seat 142 and valve member 144, such as a ball, are formed ofthe same non-ferromagnetic material such as synthetic ruby. In otherconstructions, the movable valve member may be a disc, a cone, or othertype of plug. A spherical ball is currently preferred because that shapeenables tight, precise tolerances, assembly and control relative to thevalve seat. Also, the position of the seat within a port can be adjustedduring assembly of the valve unit to alter the actual performance valueachieved at each setting, using a force versus displacementrelationship. First, a mandrel checks the position of the ball, and theseat is inserted to an estimated desirable location within the port.Ball displacement is tested at one or more settings to confirm thatdesired performance will be achieved.

Valve unit 100 a, FIG. 1A, includes a monolithic rotor 120 a havingpockets carrying magnetic elements 125 a and 123 a each having north Nand south S magnetic orientations. Instead of a separate housing elementwhich is molded independently and then attached to the lower rotor unitto form a combined rotor construct such as shown in FIGS. 1 and 2, rotor120 a is a different type of rotating construct that is micro-moldedwith pockets in the upper housing portion 124 a of the rotor 120 atogether with lower cam portion 122 a. Magnetic elements 123 a, 125 aand tantalum reference ball 129 a then are placed in the pockets.Thereafter, epoxy such as Loctite® M-31CL™ epoxy is added to fill inremaining voids in the pockets to complete the rotor 120 a. Axle 126 ais shown as a separate component which is added to rotor 120 a after itis removed from the micro-mold; in another construction, axle 126 a isco-molded with the main rotor 120 a. Also shown in FIG. 1A are rotorteeth 160 a and 162 a, movable valve element limiter 180 a and a portionof spring element 134 a pressing ball 144 a against valve seat 142 a. Inan alternative construction, rotor teeth 160 a, 162 a are positionedbelow the cam portion 122 a instead of projecting below the housingportion 124 a as illustrated.

Valve unit 100 is shown assembled in FIGS. 3-5 and positioned at asecond pressure setting, as described in more detail below. Rotorhousing 124 carries downwardly projecting teeth 160 and 162 withcooperate with four lock stops projecting upwardly from lower casing 106in this construction. Lock stop 172 is shown in partial cross-section inFIG. 4 and lock stops 170 and 176 are visible in FIG. 5. Preferably, thelower surfaces of rotor teeth 160 and 162 are rounded and the uppersurfaces of casing lock stops 170, 172, 174 and 176 each have aplurality of facets to create a chisel-like, lead-in topography whichencourages the rotor teeth to return to a constrained position. However,the vertical surfaces of teeth 160, 162 and of stops 170-176 abut whenengaged and do not “lead out”, that is, relative translational movementis discouraged. Pure vertical lift must be provided by an adjustmenttool, as described in more detail below, to overcome the tooth-to-stopabutment and change the performance setting.

A limiter 180, FIG. 4, restricts travel of spring 134 away from seat 142so that ball 144 does not become misaligned or dislodged relative toseat 142. A gasket 182 of epoxy is shown in FIGS. 4 and 5 as anoptional, redundant seal between upper casing 104 and lower casing 106in this construction.

The operation of valve units 100 and 100 a are similar and areillustrated in FIGS. 6-8 in relation to valve unit 100, with identicalreference numerals identifying identical components and features. Notall such components and features are labelled in each drawing for thesake of visual clarity. FIGS. 6 and 6A show different levels of toppartial cross-sectional views for valve unit 100 at a first pressuresetting. Cam follower 132 slidably contacts only a first cam surface191, which has an arc length bounded by points 190 and 192, becauserotor housing tooth 162 is captured between casing lock stops 170 and172 in the normal, constrained condition. First cam surface 191 has afirst, preferably shortest radial distance 210 relative to the axis ofrotation of rotor 120. By comparison, outermost cam surface 205 has agreatest radial distance 218 as described in more detail below. Anoptional torsion spring 220 is shown in greater detail in FIG. 9.

When rotor 120 is translated upwardly by magnets in an adjustment toolas described below, rotor tooth 162 is lifted so that subsequentclockwise or counter-clockwise rotation of the adjustment tool rotatestooth 162 up and over casing lock stop 172. After the adjustment tool isremoved and when the second pressure setting has been selected as shownin FIG. 6B, rotor 120 is biased downwardly by spring 150, FIGS. 2, 4 and5.

Rotor tooth 160 is illustrated as not being in contact with any stop inFIGS. 4 and 6B, for example, because in the constrained condition rotortooth 162 is now captured between a pair of lock stops 172 and 174, FIG.6B, which is sufficient to prevent rotation of rotor 120 relative to thecam follower 132 beyond points 192 and 194 on the cam structure of rotor120. Points 192 and 194 represent a second arc length for second camsurface 193. Surface 193 is at a second radial distance 212 which isgreater than distance 210 and is less than distance 218, FIGS. 6A and6H. The arc length of second cam surface 193, FIG. 6B, can be the sameor different than the arc length of first cam surface 191 but,preferably, is substantially the same length.

The outward radial motion of cam follower 132 as it slidably travelsfrom first cam surface 191, FIG. 6A, to second cam surface 193, FIG. 6B,increases the biasing force by valve spring 134 on ball 144 as increasedtorque is applied by cam follower 132 to the remainder of spring armunit 130. Improved precision in pressure control is achieved by having astiff cam follower 132 in contact with the selected cam surface and aflexible element, spring 134, in contact with the valve ball 144. Theenhanced result is opening of the ball 144 from the valve seat 142 byrequiring only the resilient spring element 134 to bend, which providesa constant spring force to the ball 144. The opening pressure, andoverall valve performance, is not reliant on axial pivoting of thespring arm unit 130.

A third opening pressure setting is shown in FIG. 6C with rotor tooth162 positioned between casing stops 174 and 176 such that cam follower132 experiences only third cam surface 195 between points 194 and 196 ata third radial distance 214. To achieve a fourth pressure setting, FIG.6D, both rotor teeth 160 and 162 are utilized relative to casing stops170 and 176, respectively. Cam follower 132 is restricted thereby tofourth cam surface 197 between points 196 and 198.

Fifth through seventh pressure settings are illustrated in FIGS. 6E-6Gas rotor tooth 160 is successively captured between casing lock stoppairs 170-172, 172-174, and 174-176, respectively. Cam follower 132 isrestricted thereby to fifth cam surface 199 between points 198 and 200,FIG. 6E, sixth cam surface 201 between points 200 and 202, FIG. 6F, andseventh cam surface 203 between points 202 and 204, FIG. 6G.

Preferred opening pressure settings currently range from approximately30 mm to 210 mm water (294 Pa to 2,059 Pa) in seven increments of 30 mm(294 Pa), with a final, “virtual off” setting described in more detailbelow. Preferably, each valve unit is calibrated and tested at the timeof manufacture at one or more flow rates. Actual opening pressure foreach setting tends to vary according to flow rate, typically measured inmillilitres per hour. Also, when tested with a 120 cm long distalcatheter having an inner diameter of 1 mm, the average opening pressuretypically will increase by 9 mm water or more at flow rates of 5 ml/h ormore.

The final setting, FIG. 6H, of approximately at least 400 mm water(3,920 Pa) minimizes flow as a “virtual off” setting, that is, assubstantially closed. This final setting is achieved by exposing camfollower 132 to outermost cam surface 205, defined by points 204 and206, having greatest radial distance 218. This greatest cam settingforces stiffener element 133 of spring arm unit 130 against valve spring134 to shorten its active, effective length and thereby dramaticallyincrease the biasing force applied against ball 144. The final openingpressure is increased by more than fifty percent over the prior setting.In other constructions, a stiffener element is forced against a valvespring during two or more final cam settings at desired pressureincrements.

Spring arm unit 130 is shown in greater detail in FIGS. 9 and 9A withcam follower 132, stiffener element 133, and valve spring 134. Camfollower 132 terminates in a triangular head 233 with rounded orchamfered edges, one of which serves as a bearing surface 235. In apreferred construction, spring element 134 is formed from stainlesssteel having a thickness of 0.020 inches and terminates in an enlargedpad 230 for contacting the valve ball or other movable valve member. Inone construction, spring element 134 is attached to the remainder ofspring arm unit 130 by a post 232 and rivet 234 which are secured byultrasonic welding. Torsion spring 220 has a first leg 221 which isretained in recess 236 of projection 238. Second spring leg 223 restsagainst an inner surface of the casing.

Use of torsion spring 220 is optional, and is possible because onlyspring element 134 contacts the movable valve member. As a result,additional spring force from torsion spring 220 can be utilized to forcebearing surface 235 of cam follower 132 against a cam surface of therotor. This biasing force provided by torsion spring 220 augmentsrotational position of the spring arm reflective of the intended camdisplacement without otherwise impacting the force applied to the ballor other movable valve member. This provides for a more accurate andrepeatable opening pressure and a more manufacturable and robust designas it reduces the need to maintain minimal friction such as when thevalve spring element solely provides the force needed to maintain thecam follower on the cam surface.

The position of the components and features within valve unit 100 at thefirst pressure setting shown in FIG. 6A is illustrated at a deeperpartial cross-sectional view in FIG. 7. Opening 222 into the lower camportion of rotor 120 inhibits negative pressure from developing underrotor 120, that is, opening 222 ensures pressure equalization ascerebrospinal fluid passes through valve unit 100.

The transition from the first pressure setting to the second pressuresetting is illustrated in FIGS. 8 and 10 as rotor 120 is translatedupwardly by magnetic attraction with an adjustment tool, such as shownin FIG. 23 below, so that rotor tooth 162 is able to clear casing lockstop 172. Cam follower 132 is shown in FIG. 8 at point 192 passing fromfirst cam surface 191 to second cam surface 193. Lower cam section 122has a sufficient height relative to cam follower bearing surface 235 toensure that cam follower 132 remains in contact with a cam surface ofcam portion 122 in both the constrained and unconstrained conditions.Rotor retention spring 150, FIG. 10, has been compressed, its biasingforce being overcome by magnetic attraction between rotor 120 and theadjustment tool while it is positioned over valve unit 100 as shown inFIG. 23. Also illustrated in FIG. 10 are upper and lower synthetic rubybearings 242 and 139 for upper and lower axles 136 and 138,respectively, of spring arm unit 130. Synthetic ruby bearing 240rotatably supports rotor axle 126.

The position of the components and features within valve unit 100 at thefinal, “virtual off” or substantially closed setting shown in FIG. 6H isdepicted at a shallower cross-sectional view in FIG. 11 in anunconstrained condition. Further clockwise rotation of rotor 120 isprevented by rotation stop or limiter 250 which projects downwardly fromupper casing 104 to contact finger 127. Rotation stop 250 contacts theopposite surface of finger 127 when rotor 120 is turned fullycounter-clockwise in an unconstrained condition. The actual position ofrotation stop 250 may be shifted to the right of the position shown inFIG. 11 so that cam follower 132 is able to track nearly the entireportion of cam surface 205. Preferably, one side of stop 250 preventsrotor movement from the lowest setting directly to the highest setting,and also prevents the cam follower from touching the cam projection forthe highest setting when the rotor is at its lowest setting. The otherside of stop 250 prevents movement from the highest setting directly tothe lowest setting. A side, partial cross-sectional view of rotationstop 250 blocking rotor housing 124, as well as spring 150 compressedbetween rotor 120 and upper casing 104, is shown in FIG. 12 for thisunconstrained condition.

Further detailed views of selected features and components of rotor 120in one construction are illustrated in FIGS. 13 and 13A. In particular,the housing portion 124 is shown as integral with cam portion 122,similar to monolithic rotor 120 a of FIG. 1A. Pocket cavity 260, FIG.13, contains magnet 123 and tantalum reference ball 129 which is readilyvisible during imaging of the valve unit 100 after implantation in apatient to confirm the actual pressure setting. Pocket cavity 262 holdsmagnet 125. A partial end view of housing portion 124 through magnet125, pocket 262 and rotor tooth 160 is provided in FIG. 13A.

In a preferred construction, unintentional setting changes are minimizedby the combination of (a) a substantially fixed, tight-tolerance,non-wobbling rotor axle, (b) abutting rotor-tooth-to-casing-stopvertical surfaces as described above, (c) a spring which biases therotor toward the constrained condition as described above, and (d)off-axis magnets within the rotor which tend to bind the axle when amagnetic field is applied to the valve unit. In other words, it ispreferable to configure the valve unit components to limit the allowableplane(s) of motion and to restrict translational movement of the rotor.The axis of magnetization of the rotor magnets preferably are arrangedto lie between forty-five degrees to ninety degrees relative to the axisof rotation of the rotor, more preferably between seventy-five toeighty-five degrees. It is also preferable to orient the north and southpoles of each magnet as described in more detail below.

It is desirable for the magnets 123 and 125 in the rotor 120 to be blockor slot shape magnets that are magnetized through thickness, that is,each of magnets 123, 123 a and 125, 125 a preferably has an axis ofmagnetization that is perpendicular to its length and width, and isarranged with north-south polarity orientation as described in moredetail below in relation to FIGS. 26A and 26B. For the constructionshown in FIG. 1A, magnets 123 a and 125 a have BHmax of approximately 35MGOe, with a length of 2.45 mm, a width of 1.45 mm and a thickness of 1mm. The term BHmax refers to the maximum energy product of a magneticmaterial, which is the magnetic field strength at the point of fullsaturation of the magnetic material measured in mega gauss oersteds.Magnets 450 and 452 in a corresponding adjustment tool 306, FIG. 21,have BHmax of 42-52 MGOe, and are axially magnetized, disc shapedmagnets with a diameter of 15.9 mm and a height of 15.9 mm. Suitablematerial, which resists demagnetization at fields up to three Tesla, forvalve unit magnets includes NdFeB, and suitable material for adjustmenttool magnets includes NdFeB grade 42-52. Suitable axially magnetizeddisc magnets 360 and 362 for an indicator tool 302, FIG. 15, have aBHmax of 42 MGOe, with a diameter of 3.18 mm and a height of 3.18 mm,and NdFeB grade 42 material.

Pressure settings for novel valve units disclosed herein preferably arenoninvasively checked and adjusted using several accessories referred toas a toolset. One construction of such accessories is illustrated inFIGS. 14-23 for toolset 300 according to the present invention. Analternative construction of an indicator tool according to the presentinvention is shown in FIGS. 24-25 below.

Toolset 300 according to the present invention includes indicator tool302, FIGS. 14, 15 and 18-20, a locator tool 304, FIGS. 14, 16, 17-20 and22-23, and adjustment tool 306, FIGS. 14 and 21-23, also referred to asan adjuster tool. Indicator tool 302 and adjuster tool 306 each can neston top of locator tool 304 as shown and described in more detail below.As illustrated in FIG. 14, toolset 300 includes in this construction astorage and transport case 308 having a smaller recess 310 for carryingadjuster 306 and a larger recess 312 for carrying indicator 302 nestedwith locator 304. Preferably, indicator release button 322 of indicator302 is received within upper recess 314 when case 308 is closed forstorage or transport of toolset 300.

An exploded view of components for indicator tool 302 is provided inFIG. 15. A pressure wheel assembly 359 includes a value wheel 350supported by yoke 336, which is fixed in track 337 of wheel 350, alsoreferred to as a readout dial. A spindle 334 rotates easily and securelyon synthetic ruby bearings 332 and 338 carried by indicator housing 340and base 370, respectively, when wheel assembly 359 is in a released orunlocked condition. Wheel 350 carries a plurality of paddles or regions,such as paddles 352 and 354 having pressure value indicia 356 and 358,respectively. Another construction having a circular disc with indiciaregions is shown and described below relative to FIG. 24. Magnets 360and 362, FIG. 15, are carried in recesses 351 and 353 of wheel 350 andpreferably are fixed with a retaining compound to metal yoke 336. In oneconstruction, yoke 336 is formed of an alloy such as Ti6Al-4V. Magnets360 and 362 have a known north-south polarity which is oriented relativeto the various value indicia on the value wheel 350 so that the properreadout will be provided when the indicator tool is placed over animplanted valve unit.

When release button 322 is depressed from a first position to a secondposition, FIG. 19A, wheel assembly 359 enters a released condition andpressure value wheel 350 is able to rotate freely on spindle 334, FIG.15. Spring 324 biases release button 322 upwardly so that gear 330 isnormally engaged in the first position by at least one catch, such asinwardly facing projections 327 and 329, formed on downward buttonextensions 326 and 328, respectively, at the lower portions of button322. Gear 330 is preferably a bevel gear, more preferably a crown gearas illustrated in FIG. 15, with at least one recess between teeth orcogs, preferably a pair of opposing recesses, for each pressure indiciato be read on wheel 350. When indicator tool 302 is positioned withlocator tool 304 over a valve unit, such as shown in FIGS. 18-20, wheelassembly 359, FIG. 15, rotates freely like a compass after button 322 isdepressed, until a north-south polarity is encountered that is strongerthan the earth's magnetic field. Unlike a compass, wheel assembly 359preferably is able to spin and properly indicate the actual setting of avalve unit regardless of the position or orientation of the indicatortool, even when indicator tool 302 is held vertically or upside-down.

Magnets 360 and 362 of indicator tool 302 are attracted to magnets inthe valve unit to be read, such as magnets 123 and 125 of valve unit 100as shown in FIG. 13, for example. When button 322 is released, spring324 biases it back to the first position, and projections 327 and 329,FIG. 15, travel upwardly to engage with a pair of recesses which areclosest to them to drive wheel assembly 359 to the closest setting andthereby lock pressure value wheel 350 so that one pressure value isclearly visible through lens 344 carried by window or opening 342defined in upper housing 340. Button 322 is able to translate orreciprocate along indicator axis of rotation IR but not rotate relativeto indicator housing 340. Biased by spring 324, button 322 therebydrives wheel assembly 359 to a discrete pressure value position.

Indicator tool 302 can be easily lifted by a clinician from storage case308 by grasping raised finger grip section 348. Indicator 302 is alignedwith locator 304 so that marker 346, FIGS. 15 and 18, aligns with marker380, FIG. 16, defined on flared surface 400 of locator tool 304. In someconstructions, actual rotation of indicator 302 relative to locator 304is prevented by a key, detent or other lock feature on one tool and acorresponding recess or matching interlock on the other tool. As shownin FIGS. 16 and 18A, for example, the interior of wall 383 of locator304 carries a projection 384, preferably a metal stop, which mates witha recess 349 in the exterior of wall 347 of indicator 302 to align thetwo tools in a fixed relationship.

Locator tool 304 provides a fixed reference relative to an implantedshunt valve SV carrying a valve unit VU as shown in phantom in FIGS. 17,19 and 20. Floor 381 of locator tool 304 defines a specially shapedupper opening 382, FIG. 16, which conforms to the implanted shunt valveSV, FIGS. 17 and 19. Additionally, lower skirt 386 of locator 304defines openings 387 and 388 which receive distal catheter DC andventricular catheter VC, respectively. Implanted components are shown inphantom in FIGS. 17 and 19, as are skin SK and skull SL of a patient.

Additional features on locator tool 304 are utilized with adjuster tool306. The interior of wall 383 defines a series of reference points suchas recesses 392 and 394, FIG. 16, each of which can receive a detentsuch as ball 426 biased by spring 424 within receptacle 422, FIGS. 21and 22A, carried by rim 428 of adjuster 306. It is desirable to have aleast one of a tactile and audible indication, such as a click sound andfeel, when ball 426 engages one of the recesses 392 or 394. Also, flaredsurface 400 carries pressure value indicia such as lowest pressuresetting 402 and highest pressure setting 404, FIG. 16, which serve asstarting points for adjuster 306 as described below.

Typically, a shunt valve having a novel valve unit is initially adjustedbefore implantation while it is still in a sterile package. Preferably,the package has a reference indicia such as an arrow. Locator tool 304is placed over the shunt valve so that marking 380, FIG. 16, or amarking (not shown) on the underside of floor 381, aligns with thepackage arrow. Indicator tool 302 is then fully seated into locator tool304 so that indicator marking 346, FIGS. 15 and 18, is aligned withlocator marking 380. Button 322 is depressed and held, such as shown inFIG. 19A, until wheel 350, also referred to as a readout dial, stopsmoving. Button 322 is then released. The current valve setting will bevisible in indicator tool window or opening 342, through lens 344, FIG.15. Indicator tool 302 is removed, with the current valve setting lockedin position by the engagement of button projections 327 and 329 withgear 330 as described above.

While the shunt valve is still in its sterile package, adjustment tool306 is inserted into locator tool 304 so that adjustment arrow 438points to the valve setting number on the locator tool 304 whichcorresponds to the actual, current valve setting. The clinician holdsthe locator tool 304 with one hand and rotates adjustment tool 306 withthe other hand until it points to the desired valve setting. Once thedesired setting is achieved, the adjustment tool 306 is lifted straightupwards a minimum of 3 cm (1.25 inches) before any horizontal motion isimparted to it to avoid possible resetting of the valve unit. It is alsodesirable to have the adjustment tool 306 spaced at least 18 cm (7inches) from the indicator tool 302 while reading the actual valvesetting to avoid possible influence on the reading.

Adjustment tool 306 preferably provides an audible click and a tactileresponse as it is turned to each setting. Locator tool 304 defines arotation stop, such as projection 384, FIG. 16, which prevents rotationof adjustment 306 directly from lowest setting 402 to highest setting404, FIG. 16, or vice versa, to mimic the rotational limits on the valverotor imposed by rotational stop 250, FIG. 11, for example. Adjustmenttool 306 defines a channel 430, FIG. 21, bounded by a radiallyprojecting arcuate stop 433 extending from edge 432 to edge 434, whichallows the adjustment tool 306 to be rotated in either direction untilan edge 432 or 434 of arcuate stop 433 contacts projection 380 oflocator tool 304.

A similar procedure is utilized to percutaneously indicate and adjustthe valve unit according to the present invention after implantation.The shunt valve is located by palpation. In one construction, theunderside of floor 381, FIG. 16, of locator 304 carries an arrow, andthat arrow is aligned with the direction of fluid flow through theimplanted valve. Opening 382 of the locator tool 304 is centered aroundthe valve unit as shown in FIG. 17. Indicator tool 302 is then placedfully into the locator tool 304 as shown in FIGS. 19 and 20 so that themarkings 346 and 380 are aligned. The button 322 is depressed and helddown, FIG. 19A, until the readout disc 350 stops moving. Button 322 isreleased and the current valve setting value is captured until button322 is again depressed for the next reading. Indicator tool 302 then isremoved.

Next, adjustment tool 306 is inserted into locator tool 304 as shown inFIGS. 22 and 23 so that arrow 438 is aligned with the current valvesetting, which is not necessarily aligned with locator marking 380 asshown in FIG. 22. With one hand holding the locator tool 304, theclinician turns the adjustment tool 306 with the other hand until arrow438 points to the desired valve setting. Preferably adjustment tool 306provides an audible click and a tactile response as described above asit is turned to each setting.

After the desired setting is reached, adjustment tool 306 is lifteddirectly away from locator tool 304 without further rotation.Preferably, indicator tool 302 is then replaced into locator tool 304and another reading is taken to confirm correct valve pressure setting.Alternatively or in addition to re-use of the indicator tool, theimplanted valve can be imaged with x-ray to confirm current valvesetting.

Returning to FIG.21, components of adjustment tool 306 include a metalyoke 454, such as a bar of 416SS stainless steel, for supporting magnets450 and 452 in a housing 460. Preferably, the poles of the magnets arealigned so that one magnet has a “north” polarity at its base while theother has an opposite, “south” polarity at its base. A cover 462 definesan opening 464 which receives arrow marker 438 in this construction asshown in FIGS. 21-23; in other constructions, marker 438 is integralwith cover 462 or is applied to its surface after molding.

An alternative indicator tool 302 a is illustrated in FIGS. 24-25 havinga wheel assembly 359 a including a circular readout dial 350 a withnumerical pressure value indicia such as a first, low setting 470 of“30” or “1”, representing 30 mm water (294 Pa), and an eighth, highsetting 472 of “400” or “8”, representing 400 mm water (3,920 Pa) as a“virtual off” setting. Gear 330 a is carried by metal yoke 336 a, towhich are attached magnets 360 a and 362 a, and spindle 334 a, whichturns freely on ruby bearings 332 a and 338 a supported by shims 474 and476, respectively, when button 322 a is depressed against the biasingforce of spring 324 a to move from a first, locked position to a second,released position.

Stops 480 and 482 of button 322 a are catches that are shown engaginghorizontal teeth of gear 330 a in FIGS. 24 and 25 in the normalcondition for indicator tool 302 a. Also shown are housing bottom 370 aand lens 344 a carried in upper housing 340 a.

Yet another alternative construction of an indicator tool according tothe present invention is shown in FIG. 26 nested in a locator tool 500defining an opening 502 in a floor 504. Indicator tool 510 has a wheelassembly 512 which includes readout dial 514 with performance settingindicia, metal yoke 516, first crown gear 522 fixed to an upper surfaceof yoke 516, magnets 518 and 520 mounted on a lower surface of yoke 516,all rotatable on bearing 517 mounted on platform 524 of indicatorhousing lower portion 534. Release button 530 has an enlarged head 531at a lower end and has a second crown gear 532, serving as a catch whenbutton 530 is in a first position, mounted by press fit at a middle axlesection of button 530. An upper end of button 530 has a narrowed keyelement 533 which is movable vertically within slot 537 defined byindicator housing upper portion 538. Rotation of button 530 is preventedby the interaction of key element 533 with the side walls of slot 537.Bearing 517 enables translational, thrust movement of button 530 as wellas enabling rotation of wheel assembly 512.

In this construction, the act of nesting indicator tool 510 into locator500 causes a portion of head 531 of release button 530 to contact aportion of locator floor 504, near opening 502, which overcomes thedownward bias provided by coil spring 540 to move button 530 from afirst, normally locked position to a second, rotatable position asillustrated in FIG. 26. The act of removing indicator tool 510 fromlocator tool 500 allows spring 540 to automatically drive second, catchgear 532 downward to mesh with first gear 522 of wheel assembly 512. Oneof the performance setting indicia on dial 514 is then readable throughmagnifying lens 528 to record the actual setting of a valve unit.

An alternative adjuster tool 600 is shown in FIGS. 27A and 27Bpositioned over skin SK of a patient P with an implanted shunt valve 10b having a valve unit 100 b, which is similar in construction to shuntvalve 10 a with valve unit 100 a as shown and described above relativeto FIG. 1A. A locator tool as described above has been omitted fromthese drawings, and everything other than a portion of shunt valve 10 b,at a scale of approximately 10× relative to adjuster tool 600, has beenomitted from FIG. 27B for clarity in discussing orientation of magneticpolarities and axes of magnetization.

Adjuster tool 600 has an upper housing 602 and a lower housing 604 withan enlarged floor portion 606 to assist securing magnets 610 and 612 inposition. Upper casing 602 has an integral directional arrow 620 forproper alignment with a locator tool and has a marker 622 which confirmsdirectional alignment of upper casing 602 with lower casing 604 duringassembly.

Adjuster magnets 610 and 612 are connected by metal yoke 608 and eachhas an axis of magnetization 614 and 616, respectively, which aresubstantially parallel in this construction as indicated with dashedlines. During adjustment of a valve unit according to the presentinvention such as valve unit 100 b, axes of magnetization 614 and 616are oriented to be substantially parallel to axis of rotation 618through axle 126 b of rotor 120 b. In this construction, adjuster magnet610 has a south pole S that is oriented to face rotor magnet 123 b andimaging reference ball 129 b while north pole N of magnet 612 isoriented to face rotor magnet 125 b. Rotor 120 b is shown in aconstrained condition in FIG. 27B, and is lifted to an unconstrainedcondition when the lower surface of adjuster tool 600 approaches withinthree cm (less than 1.25 inches) of the floor of a locator toolpositioned on skin SK, FIG. 27A.

Axis of magnetization 630 of rotor magnet 123 b is shown having an angle632 relative to axis of rotation 618, with north pole N facing radiallyoutwardly relative to axis of rotation 618. Rotor magnet 125 b has asimilar axis of magnetization, but with south pole S facing radiallyoutwardly away from axis of rotation 618. Angle 632 is approximatelyeighty degrees in this construction. While an angle of ninety degreesfrom axis of rotation 618 for the axes of magnetization for rotormagnets 123 b and 125 b may be most effective for detection of actualsetting by an indicator tool according to the present invention, it hasbeen found that offset angles of seventy-five to eighty-five degrees,most preferably approximately eighty degrees, are suitable forinteraction with the adjustment tool 600. Further, having axes ofmagnetization other than zero degrees and ninety degrees reduces thelikelihood of simultaneous de-magnetization of both rotor magnets whenexposed to a magnetic field greater than 3 Tesla or other largeelectromagnetic field. In other words, it is preferable for the axes ofmagnetization of the rotor magnets to be offset relative to each otherinstead of parallel to each other to resist de-magnetization as well asto encourage binding of axle 126 b when exposed to unintended magneticfields.

Instead of controlling opening pressure as described above, the rate offlow of a bodily fluid can be controlled using adjustable performancesettings to regulate passage of the bodily fluid. A port 700, FIGS. 28and 29, such as an inlet or an outlet for the bodily fluid in a casing702, has a valve mechanism of a spring arm unit positioned at the port.The valve mechanism includes a movable valve member such as member 710.Only the distal portion of valve member 710 is shown, terminating indistal end 720. A spring arm unit, otherwise substantially similar toconfigurations described above, has a cam follower arm in slidablecontact with the cam surfaces of a rotor and has a resilient springelement applying a closing effect with the valve member 710 at the port700 to establish a flow control setting as the performance setting forthe valve unit. Sufficient rotation of the rotor to change the camsurface in contact with the cam follower alters the closing effect withwhich the valve member moves relative to the port, such as by impartinga sliding action indicated by arrow 722, FIG. 29 as the spring arm unitpivots, and thereby alters the performance setting of the valve unit ina linear or non-linear manner as desired.

In this construction, movable valve member 710 is integral with theresilient spring element and defines a non-linear orifice 712 having awide edge 714 and a narrow edge 716. A closed region 718 provides asubstantially closed, minimal-flow setting. Fixed guides 730 and 732,FIG. 29, maintain the valve member 710 proximate to inner surface 734 ofcasing 702.

The distal end of another construction of a movable valve member 710 afor controlling flow is illustrated in side view in FIG. 30. An initialsection 740 is linear. Member 710 a then increases in height beginningat point 742 until a maximum height is reached at point 744 to provideprogressive restriction of a port as member 710 a is moved in thedirection of arrow 748. A closed region 746 preferably is larger inheight than the diameter of a port to be closed, such as an inlet or anoutlet to a housing.

In many circumstances, more accurate positioning of a tool set relativeto an implanted programmable valve or other adjustable device can beaccomplished by determining both the location and orientation of theimplant. It is desirable to decrease reliance on the accuracy of a userwhile positioning the tool set and to increase the likelihood ofaccurate indication of actual performance setting of the implant.Positioning tools and methods according to the present invention guide auser towards appropriate positioning of tools to more accuratelyindicate and adjust the setting of an adjustable implant such as aprogrammable shunt valve device.

A positioning tool 800 according to the present invention is shown inFIGS. 31 and 31A having a body 802 defining a centrally located accesshole 804, intended to be directly positioned over the implant withbottom surface 801 resting against the skin of a patient, into whichfits an adjustment tool 810, FIGS. 33 and 33A, having a body 816 and ahandle 818 suitable for gripping by a thumb and a finger of a userwearing gloves, or between two gloved fingers of the user, to enablemanipulation of adjustment tool 810 as described in more detail below.

Preferably, mechanical interference between the dimensions of the hole804 and the adjustment tool 810, which in some constructions is enhancedby a rib, a ridge, or another feature on the periphery of at least oneof the hole 804 and body 816 of adjustment tool 810, would limit theinward travel of the adjustment tool 810 to minimize or avoid protrusionbeneath the positioning tool 800. It is also desirable to maintainalignment of the adjustment tool 810 if the implant were to protrudeinto the hole 804 to bring the patient's skin in contact with theadjustment tool 810.

The positioning tool 800 also defines a storage cavity 806 to hold theadjustment tool 810 and, preferably, with a material such as nickel ironalloy to contain, that is, to absorb and redirect, the magnetic fluxemanating from the magnets 812 and 814 within body 816 while adjustmenttool 810 is not being utilized. This storage, preferably with shielding,is intended as a safe place for the magnets 812 and 814, so that they donot interfere with the magnetic field sensing capability of thepositioning tool 800, which is described in more detail below. The terms“magnet” and “magnets” as utilized herein include metals and alloyshaving properties of attracting or repelling iron as well aselectromechanical mechanisms for generating similar magnetic fields.

Positioning tool 800 includes a display 803 in this construction toenable the user to select the mode of operation and to provide visualfeedback to the user. Also included is a power button 805 and aselection button 807 to enable the user to navigate the through menudriven options. Internal circuitry and an energy source such as abattery are also contained within body 802 in this construction. Onetechnique for operating positioning tool 800 is described below inrelation to FIGS. 35-39.

An alternative positioning tool 820, FIGS. 32 and 32A includes amoveable bezel 822 with the numbers 1 through 8 corresponding to theimplant settings, an indicator mark 824 on setting #2, and indications826 of degrees on body 828 of tool 820, shown in FIG. 32 in five degreeincrements from zero to twenty degrees. These could be used in theoptimize tool orientation method described below as an alternativeprocedure in relation to FIGS. 38-39, where the 1^(st) & 2^(nd) RC(Rotational Construct, also referred to as a rotor) orientations havebeen found and then utilized to calculate how far out of orientation thetool is, where this number is delivered to the user so that the bezel822 can be adjusted, such as by manual rotation, to achieve properorientation. As one example, the user moves the bezel 822 so the mark824 on the center of setting 2 is at the 5 degrees mark on body 828. Thebody 828 further defines an access hole 830, an adjustment tool storagerecess 832, a power button 834, a display 836, and a mode selectionbutton 838 in this construction.

An adjustment tool 840, FIGS. 34-34A, includes an additional magnet 843,located in handle 848 on the opposite end to magnets 842 and 844 withinbody 846, to facilitate moving the RC during the process described belowin relation to FIGS. 38-39 wherein the adjustment tool 840 is invertedand rotated, while exposing the single pole magnetic field of magnet 843to the implant. Recess 832 is sufficiently deep, as shown in FIG. 32A,to store adjustment tool 840 and, preferably, contain (absorb andredirect) magnetic flux so as to shield the magnetic field of adjustmenttool 840 from other components of positioning tool 820.

Several techniques to optimize tool location and position areillustrated in FIGS. 35-39. FIGS. 35 and 36 are flow charts showing atechnique 900 according to the present invention to optimize toollocation. A user estimates, step 902, the location of an implant such asa programmable valve, such as by palpation, and places, step 904, apositioning tool according to the present invention at the approximatelocation of the implant. The user orients the tool relative to theapproximated longitudinal axis of the valve, that is, in the directionof flow through the implanted valve. Next the user selects and initiatesactive magnetic field detection, step 906, utilizing the positioningtool, wherein the tool first confirms that sufficient field strength isdetected, step 908. If not, the logic returns to step 902, providingaudio and/or visual guidance to the user such as via displays 803 or836, FIGS. 31 and 32, respectively. One type of sensor array toaccomplish magnetic field detection is described below in relation toFIG. 40.

Once sufficient field strength is confirmed in step 908, FIG. 35, in oneconstruction the logic proceeds, line 912 to circled A, to detect thelocation of the maximum positive and negative poles, step 914, FIG. 36.The display actively provides visual and/or audio feedback, step 916,with return to estimating the location of the implant as shown bycircled B to step 902, as the user moves the position of the tool untilthe tool senses that it is concentric with the implant, line 918. Anoptional “position optimized?” step 920, shown in phantom, is discussedbelow.

In one procedure, the tool next determines the implant setting bydetermining, step 922, and comparing, step 924, the RC angle, that is,the angle between the user-approximated direction of flow and the linethat passes through the detected maximum positive and negative peaksfrom the magnets in the RC, versus a lookup table that has ranges foreach implant setting based on perfect direction of flow.

FIG. 37 is a flow chart illustrating optimization of tool position,represented by optional step 920, FIG. 36, such as by changing roll orpitch of the tool. The user first optimizes the tool location, steps 902to 916 as described above. The tool is then utilized, line 930 tocircled C proceeding to step 932, FIG. 37, to compare the magnitude ofthe maximum positive and negative peaks, wherein the field from theidentical implant magnets should be detected as identical, step 934,when the tool is placed parallel to the implant. The tool display wouldconvey to the user the detected imbalance in vector form, and this wouldactively change as the user manipulates the roll and pitch of the tool,the logic returning via line 936 to circled B to step 902, FIG. 35, withthe goal to achieve no visual vector of imbalance, line 938 to circledE, FIG. 37, proceeding to step 922, FIG. 36.

FIG. 38 is a flow chart showing details for optional optimization oftool orientation, step 940, FIG. 37, such as by detecting yaw relativeto a programmable implant having “setting pockets”, also referred to as“pockets”, such as the first space or pocket established between lockstops 170 and 172, FIG. 6A, for a first performance setting and thesecond space or pocket established between lock stops 172 and 174, FIG.6B, for a second performance setting, wherein an RC such as a rotor canmove within each pocket without changing the performance setting. Inthis construction the user magnetically moves, step 950 in FIG. 38, theimplant RC to one end of the setting pocket, the tool detects the RCangle, step 952, and then the user repeats the move, step 954, for theopposite end of that pocket for the same setting, step 956. In oneconstruction, the maximum angular range of RC movement within a pocketis approximately 34 degrees for an implant having eight performancesettings. One specialized tool for accomplishing the “pocket check”range of RC movement is adjustment tool 840, FIGS. 34-34A, withadditional “checking” single magnet 843 as described above. In otherwords, while two magnets are preferred to lift the RC and shift it to adifferent pocket, only a single “checking” magnet is needed for a“pocket check” to confirm the actual pocket that the RC is occupying.Additionally, a “checking” magnet having an opposite polarity is desiredto attract the closest RC magnet instead of trying to repel the RCmagnet during the pocket check. In another construction, one or more“checking” magnets are located within a tool that automatically andsequentially attracts the RC to the angular limits of the settingpocket.

In one procedure, the logic proceeds to circled F and to step 924, FIG.36, with a more accurate valve setting displayed, step 926. The angularrange-of-movement window described by the two arcuate ends of the pocketis information that, when compared to a lookup table, step 924, wouldsignificantly increase the level of confidence of the reported implantsetting. In other words, with only a single RC angle that is near theborder between two settings, an incorrect determination can more easilybe made than in the case where an RC window (formed by two angles) isprovided, that is smaller than the setting window, so that simply thelargest percent of the RC window that resides in any particular implantsetting window determines the Implant setting.

For example, if the tool detects a field that is 37 degrees relative tothe assumed longitudinal axis of the implant, it could be interpreted aseither setting #2 or setting #3. However, when the RC is moved to theextremes of rotational travel within a pocket, without changing theperformance setting of the implant, if the detected field ranges from 35degrees to 62 degrees, the implant must be at setting #2. By comparison,if the detected field ranges from 15 degrees to 38 degrees, it must beat setting #3. Neither precise positioning of the tool nor repositioningof the tool for the purpose of setting indication is necessary, unlessgross miss-positioning of the tool is detected.

In another construction, the logic proceeds from step 920, FIG. 36,directly to step 950, FIG. 38, as shown by the dash-circled C at the topof FIG. 38. In yet another construction, the logic proceeds from step956, FIG. 38, to step 932, FIG. 37, as shown by the dash-circled F atthe top of FIG. 37.

FIG. 39 is a flow chart showing optional further steps from step 956,FIG. 38, via dash-circled letter G to step 960, FIG. 39, to optimizetool orientation by moving all or a portion of a tool. In addition togreater confidence in the setting reading, this method can be used toprovide feedback to the user to correct the tool yaw. Improved tool yawensures that, during the adjustment of the implant, the adjustmentmagnet properly de-couples with the RC when it is positioned in thecenter of the pocket, so that it can drop in the correct setting pocketand enter the ‘locked’ position immediately. The feedback, step 960, canbe in a manner similar to the Optimize Tool Location method of FIGS.35-36, wherein the user rotates the tool, step 962, until, for example,a visible seconds hand reaches 12 o'clock position. After each rotationof the tool or a portion thereof, such as by holding the bezel 822 inposition while moving the tool body 828, FIG. 32, or by moving only thebezel as described below, the logic proceeds as shown by circled D tostep 950, FIG. 38. When the tool is correctly oriented, step 960, thelogic proceeds as shown by circled F to step 924, FIG. 36.

Alternatively the display provides a numerical output to the user thatreferences markings on the positioning tool and markings on a rotatablebezel. For example, if the tool is intended to be oriented such that thelongitudinal axis of the tool is aligned with the direction of flowthrough the implant, then the setting #2 should be at approximately 6o'clock. In FIG. 32, the moveable bezel 822 has a mark 824 for thecenter of setting #2, and the tool 820 has angular increments 826. Herethe display 836 can convey to the user that, based on the detected RCwindow, the current orientation of the bezel should be rotated to alignthe mark at setting #2 with some value in degrees on the Tool, tocorrect the yaw of the bezel, where the bezel will dictate the positionof the adjustment magnet upon completion of the implant setting changeprocedure.

FIG. 40 is a schematic diagram of three sensor arrays 1002, 1004 and1006 for a positioning tool 1000 according to the present invention,each array sensing three different axes (a) X, Y, Z, (b) X′, Y′, Z′ and(c) X″, Y″ and Z″, respectively. In one construction, each array 1002,1004 and 1006 has three Hall effect sensors, each sensor arranged alongan axis different from that of the other sensors. In otherconstructions, each array has one, two, or differing numbers of sensors.Working together, the sensor arrays preferably are able to detect themagnetic field midpoint between the north and south poles of the RC(Rotational Construct) of the implanted programmable valve, as well asthe relative direction of the field, or axis of the field, inthree-dimensional space. This information is then utilized to direct theuser to best position the locator and/or indicator tools relative to theimplanted valve.

FIGS. 41A and 41B are examples of displayed mode and guidance to a user,respectively, such as for the display screens shown in FIGS. 31 and 32.Screen 1010, FIG. 41A, displays message 1013 stating “OPTIMIZE LOCATION”to indentify the selected mode, such as the mode depicted in FIGS.35-36. Screen 1014, FIG. 41B, displays a directional arrow 1016 to guidethe user to move the tool in the indicated direction. In oneconstruction, arrow 1016 is a vector-type arrow in which the amount ofdistance to be traveled is depicted by the length or other magnitude ofarrow 1016.

FIGS. 42A-42C are top views of alternative displays 1024 guiding a userutilizing indicator tool 1020 which, in one construction, is positionedwithin a locator tool 1022. The centered dot or small circle 1026 a,FIG. 42A, depicts the desired centered, concentric location over theimplanted valve, as represented by dashed oval or lozenge-shaped image1028 a. Arrow 1026 b, FIG. 42B, indicates movement needed to achievecentering over the implanted valve, represented by image 1028 b.Similarly, arrow 1026 c, FIG. 42C, provides another example of thedirection a user should move the indicator and/or locator tools toachieve an optimum location relative to image 1028 c.

Magnetic detection of an implanted valve is limited both by the qualityof the sensing capabilities of the detection tool as well as by theproximity to the implanted valve that is afforded to the sensors of thetool. Limiting how close the sensors can be positioned relative to eachother and to the implanted valve can result in less than optimum settingindication and adjustment. Additionally, exposure of sensors to asignificant magnetic field can affect the performance of the sensors, tothe extent that additional steps must be performed to re-zero orre-calibrate the sensors.

Several constructions of an improved positioning toolset according tothe present invention have an indicator tool which is also referred toas a detection tool, one or more locator features such as a separatelocator tool or integral locator elements, and an adjustment tool which,in some constructions, also has locator elements. The detection toolelectronically senses the location of the implanted valve and providesfeedback to the user to optimize the position of the tool relative tothe implanted valve. The detection tool is capable of detecting thevalve setting based on the direction of the magnetic field detected,instead of relying on the orientation of the tool as positioned by theuser based on an estimate of valve orientation.

The locator feature utilizes the optimized location from the detectiontool to establish the same optimal position for subsequent placement ofthe adjustment tool. In one construction, a detection tool 1030according to the present invention, FIG. 43, having a liquid crystal orlight-emitting diode display 1032 within a rim 1034 above a body 1036,is placed into opening 1042 of a separate locator tool 1040, FIG. 44,having markings 1044 on a rim 1045 above a body 1047, and a floor 1046preferably having an implant-shaped cutout as described above.

Detection tool 1030 nested within locator tool 1040 is placed upon thepatient in the vicinity of the implanted valve. A user is then promptedvisually via display 1032 and/or by audio commands generated by tool1030 to move the position of the nested tools to achieve an optimallocation directly above the implanted valve, such as described above inrelation to FIGS. 35-39. Once an optimum position is achieved, detectiontool 1030 indicates the actual setting of the valve, and then detectiontool 1030 is removed while locator tool 1040 is kept in position.

An adjustment tool 1050, FIG. 45, having a body 1052 containing one ormore magnets and having a handle 1054, is then nested within the locatortool 1040 and utilized as described above to alter the valve setting asdesired. Markings 1044 on rim 1045 guide the user during rotation of theadjustment tool 1050 to the desired setting. Confirmation of the valvesetting change can be performed by exchanging the adjustment tool 1050with the detection tool 1030 while maintaining locator tool 1040 in thesame position, or by removing both the locator tool 1040 and theadjustment tool 1050 before returning detection tool 1030 to thatposition on the patient.

Another construction of an improved toolset according to the presentinvention has a detection tool with integral external locator features,and an adjustment tool with similar external locator features. Detectiontool 1060, FIG. 46, has a display 1062 within a body 1064 and markingguides 1066 and 1068 which are placed in proximity to the skin of apatient. A user follows prompts from detection tool 1060 to achieve anoptimal location directly above an implanted valve, and then displaygenerates an audio and/or visual indication of current valve setting. Astandard pen or skin marker is then utilized by a user to create visiblemarks on the patient using marking guides 1066 and 1068 for reference.Detection tool 1060 is then removed.

An adjustment tool 1070, FIG. 47, is then positioned on the patient toalign marking guides 1076 and 1078 on body 1072 with the visible markson the patient. Adjustment member 1050 a with handle 1054 a and internalmagnets is then rotated within body 1072 to change valve setting asdesired with reference to markings 1074 on body 1072, which is heldstationary. Confirmation of correct valve setting can be performed byexchanging detection tool 1060 for adjustment tool 1070 using thevisible marks on the patient for reference.

As will be readily apparent from the above description, independentdetection and adjustment tools according to one aspect of the presentinvention enables the detection tool to be smaller, simpler, andgenerally isolated from magnets within the adjustment tool. Thiseliminates the need to re-zero sensors within the detection tool thatwould otherwise occur if the detection tool was exposed to one or moremagnetic fields of the adjustment tool. In some constructions, sensorscan be placed closer together within the detection tool to enable moreprecise detection of the magnetic field of one or more magnetsassociated with the implant. In certain constructions, instead of Halleffect sensors, one or more sensor arrays are an array of other types ofmagnet field sensors, including purpose-built sensors, capable ofdetecting the three-dimensional orientation of a magnetic field. In anumber of constructions, the array is a solid state componentincorporating multiple single- or multi-plane magnetic field detectors.

Thus, while there have been shown, described, and pointed outfundamental novel features of the invention as applied to a preferredembodiment thereof, it will be understood that various omissions,substitutions, and changes in the form and details of the devicesillustrated, and in their operation, may be made by those skilled in theart without departing from the spirit and scope of the invention. Forexample, it is expressly intended that all combinations of thoseelements and/or steps that perform substantially the same function, insubstantially the same way, to achieve the same results be within thescope of the invention. Substitutions of elements from one describedembodiment to another are also fully intended and contemplated. It isalso to be understood that the drawings are not necessarily drawn toscale, but that they are merely conceptual in nature. It is theintention, therefore, to be limited only as indicated by the scope ofthe claims appended hereto.

Every issued patent, pending patent application, publication, journalarticle, book or any other reference cited herein is each incorporatedby reference in their entirety.

What is claimed is:
 1. A valve unit capable of being implanted in apatient and having adjustable performance settings to regulate passageof a bodily fluid, comprising: a casing defining a port for the bodilyfluid; a valve mechanism positioned at the port and including a movablevalve member; a rotor disposed at a first location in the casing andhaving an axle which rotates about an axis of rotation, the rotor isalso movable along the axis of rotation from a constrained condition, inwhich the rotor is constrained to rotate in an arc of predeterminedangular distance, to an unconstrained condition; and a spring arm unitdisposed at a second location in the casing having a cam follower arm inslidable contact with the rotor and having a resilient spring elementapplying a closing effect with the movable valve member at the port toestablish a performance setting for the valve unit; wherein sufficientrotation of the rotor alters the closing effect with which the valvemember moves relative to the port, and thereby alters the performancesetting of the valve unit; the casing defines a plurality of lock stopsand the rotor defines at least one tooth which is engagable with atleast one lock stop when the rotor is in the constrained condition andwhich does not engage the lock stops when the rotor is in theunconstrained condition.
 2. The valve unit of claim 1 wherein the valvemember defines at least one port restricting element alignable with theport in a plurality of positions to control flow through the valve unit.3. The valve unit of claim 1 wherein the valve member is integral withthe resilient spring element and is slidable to progressively restrictthe port to establish a plurality of flow control settings.
 4. The valveunit of claim 1 wherein the rotor includes magnetically attractableelements.
 5. The valve unit of claim 4 wherein the rotor includes atleast two magnets as the magnetically attractable elements, each magnethaving an axis of magnetization that is transverse to the axis ofrotation.
 6. The valve unit of claim 5 wherein the magnets are spaced onopposite sides of the rotor and each magnet has an axis of magnetizationthat is arranged to lie between forty-five degrees to ninety degreesrelative to the axis of rotation.
 7. The valve unit of claim 6 incombination with a setting adjuster tool positionable in proximity withthe valve unit, exterior to the patient, and having magnets which havesufficient attractive strength with the magnetically attractableelements to lift the rotor from the constrained condition to theunconstrained condition to enable adjustment of the rotor from an actualsetting to another setting.
 8. The valve unit of claim 7 wherein theadjuster magnets have at least one axis of magnetization that isalignable substantially in parallel with the axis of rotation of therotor.
 9. The valve unit of claim 8 in combination with a settingindicator tool positionable in proximity with the valve unit, exteriorto the patient, and capable of detecting an actual setting of the valveunit without altering the actual setting.
 10. The valve unit of claim 9wherein the indicator tool includes a gear and a wheel which rotatessubstantially freely in a detection condition when it is disengagedrelative to the gear and which is driven to a discrete setting value bythe gear in a locked condition.